Title: The common origin of star clusters and UCDs: a numerical perspective

Abstract:
Observational surveys of dense compact objects in the local Universe highlighted the co-
existense of star clusters and objects up to several order of magnitude more massive, the ultra 
compact dwarf galaxies (UCDs). It''s yet unclear whether both families lie on a continuous 
mass-size sequence, or if a bimodality can be found. Understanding the formation and evolution 
scenarios of these objects is thus key to either tell them apart, or to reveal their common origin. 
Using a parsec-resolution simulation of a galaxy merger (the Antennae), I will present the 
properties of the stellar objects formed during the interaction. I will focus on massive (10^{6-8} 
Msun) objects, their formation history (monolithic or hierarchical) and their evolution in the tidal 
field of the merger. I will conclude that the UCDs in the simulation lie at the massive end of the 
star cluster distribution, with no clear separation between the two families, thus keeping the star 
cluster - galaxy interface blurry. I will also discuss the aborted formation of a tidal dwarf galaxy, 
leading instead to a massive, very compact star cluster in galactic tidal debris.